Duplicating machine printing drum mounting construction



Dec. 3, 1968 w; D. BOATMAN I DUPLICATING MACHINE PRINTING DRUM MOUNTING CONSTRUCTION Filed March 23, 1967 4 Sheets-Sheep 1 INVENTOR.

WILLIHM D. BOQTMAN HTT NEYS Dec. 3, 1968 w. D. BOATMAN 3,413,921

,DUPLICATING MACHINE PRINTING DRUM MOUNTING CONSTRUCTION Filed March 23, 1967 4 Sheets-Sheet 5 INVENTOR.

WILLIAM D. BOQTMAN FITTOR EYS Dec. 3, 1968 w. D. BOATMAN DUPLICATING MACHINE PRINTING DRUM MOUNTING CONSTRUCTION Filed March 23, 1967 4 Sheets-Sheet 4 mm M ms 8 g 3} r bb Qm Q) n R g @b y S. @x mm vm Q0 INVENTOR.

United States Patent 3,413,921 DUPLICATING MACHINE PRINTING DRUM MOUNTING CONSTRUCTION William D. Boatman, Fridley, Minn., assignor to Dymo Industries, Inc., Emeryville, Calif., a corporation of California Filed Mar. 23, 1967, Ser. No. 625,360 22 Claims. (Cl. 101--248) ABSTRACT OF THE DISCLOSURE A duplicating machine construction in which the printing drum is mounted for rotation by frusto-conical arbor members received within recesses in the ends of the drum and frictionally gripping the perimeter of each recess for driving engagement. One arbor member is connected to a drive for rotating the drum and an arbor member is selectively movable axially to disengage the drum from the drive for allowing selective rotation of the drum relative to the drive and for permitting selective removal of the drum from the machine.

The present invention relates generally to duplicating machines of the type having a printing drum mounted for rotation by drive means in the machine and pertains more specifically to a system for mounting the printing drum within the machine such that the drum may be selectively rotated relative to the drive means and may be selectively removed from the machine with ease.

Duplicating machines which employ printing drums, such as a stencil duplicator, are now common in offices which require simple and rapid production of duplicate printed matter in large quantities. The widespread use of such machines by a variety of ofiice personnel has led to the requirement for simplified operation as well as for less complex, more economical construction. Among those operations which should be maintained simple is the disengagement of the printing drum from the drive mechanism of the machine to permit the manual rotation of the printing drum relative to the drive means for selectively adjusting the registration of the printed matter upon the printed page. Additionally, it is necessary to remove the drum from the machine from time to time and that operation should be made as easy as possible.

It is therefore an important object of the invention to provide a duplicating machine having a printing drum mounted for rotation therein by a drive means, the printing drum being readily disengaged from the drive means for enabling manual rotation of the drum relative to the drive means to permit adjustment of the registration of the printed matter upon the printed page, and the printing drum being easily removed from the machine without requiring complete dismantling of the machine.

Another object of the invention is to provide a duplicating machine as described above wherein adjustment of the registration of the printed matter upon the printed page may be accomplished without requiring that the operator touch or handle the printing drum itself.

A further object of the invention is to provide a duplicating machine having a simplified construction which may readily be fabricated and requires relatively inexpensive manufacturing and assembly techniques.

The invention attains the above objects, as well as further objects and advantages, and may be described briefly as a system for mounting and rotating the printing drum within a duplicating machine having a printing drum including a generally cylindrical body extending axially between opposite ends, the system comprising support means mounted for rotation within the machine adjacent each end of the drum, at least one of which sup- 3,413,921 Patented Dec. 3, 1968 port means includes a first generally frusto-conical surface coaxial with the axis of rotation of the drum, drive means engaged with at least one of the support means for rotatably driving the so-engaged support means, mounting means in each end of the drum, each including a configuration complementary to the corresponding configuration of the support means adjacent the corresponding end of the drum for mounting the drum in the machine between the support means, at least one of which mounting means includes a second generally frustoconical surface coaxial with the axis of rotation of the drum and cooperatively engaging the first generally frustoconical surface with sufficient gripping force to permit concurrent rotation of the drum and the support means which includes the first generally frusto-conical surface, and means for selectively displacing at least one of the support means axially relative to the other of the support means to accomplish selective disengagement of the driven support means from a corresponding mounting means and permit selective rotation of the drum relative to the disengaged support means. In addition, the invention may include means for permitting displacement of at least one of the support means axially relative to the other of the support means until the support means are spaced apart axially a sufiicient distance to permit disengagement of all such support means from the corresponding mounting means and allow lateral removal of the drum from between the support means.

The invention will be more fully understood and further objects and advantages will become apparent in the following detailed description of an embodiment of the invention illustrated in the accompanying drawing, in which:

FIGURE 1 is a generally diagrammatic plan view of a printing drum supported in a duplicating machine by a drum mounting system constructed in accordance with the invention;

FIGURE 2 is an end elevational view taken along line 22 of FIGURE 1;

FIGURE 3 is an enlarged longitudinal cross-sectional view illustrating the component parts of the system of FIGURE 1;

FIGURE 4 is a longitudinal cross-sectional view similar to FIGURE 3 with the component parts in another operating position showing disengagement of the drum from the driven support means; and

FIGURE 5 is a longitudinal cross-sectional view similar to FIGURES 3 and 4 with the component parts in still another operating position illustrating disengagement of the drum from all support means.

Referring now to the drawing, and especially to FIG- URES 1 and 2, a portion of a typical duplicating machine is illustrated at 10 and is seen to have a generally cylindrical printing drum 12 supported therein between upstanding portions 14, 15 and 16 of the frame of the duplicating machine. During ordinary operation of the duplicating machine 10, the printing drum is rotated by means of a drive pulley 18 fixed to a drive shaft 20 which is engaged with first end 22 of the printing drum 12 in a manner which will be explained in greater detail below. A support shaft 24 is engaged with second end 26 of the printing drum 12 and carries a hand wheel 28 for permitting manual rotation of the printing drum in a manner which will be explained below.

Turning now to FIGURES 3 through 5, the drive shaft 20 is journaled for rotation within the duplicating machine 10 by means of an end thrust bearing 30 fixed within the frame portion 14 at end 32 of the drive shaft 20 and a bushing 34 carried in the frame portion 15 intermediate the ends of the drive shaft. The drive pulley 18 is secured to the drive shaft 20 so that a drive belt (not shown) received within the sheave 38 of the pulley will rotate the drive shaft. The printing drum 12 is mounted for rotation with the drive shaft and with the support shaft 24 by support means shown in the form of arbor members and 42, arbor member 40 being fixed to the other end 44 of the drive shaft 20 for rotation therewith by the provision of a D-shaped cross-section at end 44 and a corresponding D-shaped recess 45 in arbor member 40, the end 44 being retained within the recess 45 by a machine screw 46, and arbor member 42 being likewise fixed to the end 47 of the support shaft 24, the support shaft 24 having a D-shaped cross-section along most of the length thereof and the arbor member 42 having a corresponding D-shaped recess 48, the end 47 being retained within the recess 48 by a machine screw 49. The arbor members 40 and 42 each have a generally frusto-conical configuration and carry generally annular members 50 and 52, respectively, of elastomeric material, such as rubber, which annular members provide frustoconical surfaces 54 and 56, respectively, coaxial with the axis of rotation of the drum adjacent each end of the drum. The ends 22 and 26 of the drum are provided with recesses and 62, respectively, each recess extending axially into the drum and having a frusto-conical surface 64 around the perimeter of the recess corresponding with the frusto-conical configuration of the surface of each annular member 50 and 52 of elastomeric material. The annular members 50 and 52 of elastomeric material engage the corresponding surfaces 64 of the recesses 60 and 62 with sufficient gripping force to permit concurrent rotation of the drum 12 and the arbor members 40 and 42 so that rotation of the drive pulley 18 by drive means within the machine will rotate the drum along with the drive shaft 20 and the support shaft 24, the support shaft being journaled for free rotation within the frame portion 16 by means of a rotating bushing mounted within a fixed bushing 72 supported in the frame portion 16 by boss portion 73. The rotating bushing 70 has a D-shaped bore 74 complementary to the D-shaped cross-section of support shaft 24 so that rotating bushing 70 and support shaft 24 will rotate concurrently.

In operating the duplicating machine it sometimes becomes necessary to rotate the drum 12 with respect to the drive shaft 20 and the drive means in order to coordinate the printing means, i.e., a stencil or the like aflixed to the outer surface of the cylindrical portion 75 of the drum, and the feed of the paper upon which the printing means will impress printed matte-r. Such coordination is necessary in order to obtain proper registration of the printed matter on a printed page. In order to accomplish selective rotation of the drum With respect to the drive shaft, the hand wheel 28 is threaded onto the rotating bushing 70 at 76 and is fixed for rotation with the rotating bushing and the support shaft 24 by means of a locking nut 77 received within a recess 78 in the hand wheel 28 and seated therein. A knob 80 is mounted for rotation upon the end portion 82 of the support shaft 24 by means of a mounting hub 84 fixed to the knob for rotation therewith and journaled upon the end portion 82, the end portion 82 of the support shaft projecting through the mounting hub 84 and receiving a jam nut 86 which is captivated on threaded portion 87 by a retaining ring 88. The mounting hub 84 is held in place against the jam nut 86 by a helical spring 90 and is threaded onto the rotating bushing 70 at 92 until the knob 80 is bottomed against the face 94 of the hand wheel 28 so that the hand wheel 28, knob 80, rotating bushing 70 and support shaft 24 will rotate as a unit. However, when it becomes necessary to rotate the printing drum 12 relative to the drive shaft 20 for registration purposes, the knob 80 is rotated relative to the hand wheel 28, the rotating bushing 70 and the support shaft 24 so as to be moved axially with respect to the hand wheel by virtue of the threads at 92 and thereby draws the support shaft 24 axially to the right, as seen in FIGURE 4, to increase the axial spacing between the arbor members 40 and 42. At this point, the driven arbor member 40 will be disengaged from the corresponding recess 60 while the freely rotatable, or floating arbor member 42 will remain engaged in the corresponding recess 62 so that manual rotation of the hand wheel 28 will rotate the drum 12 relative to the disengaged arbor member and the drive pulley 18 and drive means. The amount of such rotation may be observed by the operator by referring to an index mark 95 (see FIGURE 1) placed at the periphery of the end 22 of the drum 12, which index mark will move relative to graduations 96 placed along the outer perimeter of a relatively stationary disk 97 fixed to the arbor member 40 by screws 98.

The above disengagement of driven arbor member 40 from the drum 12 without a corresponding disengagement of floating arbor member 42 from recess 62 is accomplished by disengaging means shown in the form of a pad 100 of elastomeric material which is secured to the arbor member 40 and which is normally compressed when the arbor member 40 is seated within recess 60, as seen in FIGURE 3, to establish an axially directed resilient biasing force tending to disengage the arbor member 40 from the recess 60. When the knob 80 and support shaft 24 are drawn to the right, as illustrated in FIGURE 4, the axial force necessary to maintain pad 100 compressed is removed and the pad is allowed to expand and push drum 12 to the right while at the same time unseating and disengaging arbor member 40 from recess 60. Although the same disengagement could be made to occur by alternate disengaging means which could include choosing an elastomeric material for the annular member 50 which is softer than the elastomeric material of annular member 52 so that such alternative disengaging means will disengage arbor member 40 from recess 60 before arbor member 42 will be disengaged from recess 62, it has been found that the manufacture, assembly and replacement of annular members 50 and 52 are simplified if both annular members are fabricated'of identical materials. In addition, the more positive action of pad 100 can reduce the necessity for relatively close tolerances in the specifications for the drum 12 as well as for the annular members 50 and 52 and will assure that arbor member 40 is consistently released while arbor member 42 remains engaged with drum 12. It is, nevertheless, feasible to employ elastomeric materials of different hardnesses for annular members 50 and 52 as an alternate disengaging means either without pad 100 or in combination with pad 100 to assure consistent release and disengagement of arbor member 40 Without disengagement of arbor member 42. In the use of such alternatives, it has been found that the driven arbor member 40 may be disengaged consistently from the corresponding recess 60 while the floating arbor member 42 remains engaged with its corresponding recess 62 during axial movement of the floating support shaft 24 away from the drive shaft 20 and the driven arbor member 40 where the durometer of the annular member 50 on the driven arbor member 40 is approximately 40 and the durometer of the elastomeric material of the annular member 52 on the floating arbor member 42 is 60.

When it is desired to remove the drum 12 entirely from the duplicating machine, the knob 80 is rotated until the threaded portion of the hub 84 is completely released from the rotating bushing 70 and is then drawn axially to the right, as seen in FIGURE 5, so as to increase the spacing between the arbor members 40 and 42 to an extent where both arbor members 40 and 42 may be released from their corresponding recesses 60 and 62 and the drum 12 may be removed from between the arbor members. The axial movement of the knob 80 and the support shaft 24 to which the knob is attached is permitted by virtue of the D-shaped cross-section of support shaft 24 which allows the support shaft to be moved axially without disturbing the rotational mounting of the support shaft 24 and the hand wheel 28 thereon.

It will be noted that when the printing drum 12 is mounted for rotation within the duplicating machine as seen in FIGURE 3, the knob 80 is bottomed on the face 94 of the hand wheel 28 and sufiicient frictional gripping force is established between the annular members 50 and 52 of elastomeric material and the corresponding recesses 60 and 62 in the ends 22 and 26 of the drum. In order to establish sufficient gripping force while still allowing selective release of the gripping force as described above, the apical angle A of each frusto-conical surfaces 54 and 56 of each annular member 50 and 52 of elastomeric material must be chosen so that these apical angles are small enough to effect frictional locking engagement between the engaged surfaces 54, 64 and 56, 64 for concurrent rotation of the drum and the arbor members and yet great enough to permit selective ready disengagement of the arbor members from the recesses by relative axial displacement of the arbor members and the recesses. It has been found that an apical angle in the order of magnitude of approximately 15 will attain the desired results.

By providing the arbor members 40 and 42 with a rela tively large diameter in comparison with the overall diameter of the generally cylindrical drum 12, axial alignment of the drum within the duplicating machine during rotation of the drum is facilitated and sufiicient engaged surface area at the engaged frusto-conical surfaces of the corresponding arbor members and recesses is obtained to effect concurrent rotation of the drum and arbor members. It has been found that where the diameter of the arbor member is in the order of magnitude of one-half the diameter of the drum, axial alignment of the drum is obtained and suflicient engaged surface area is established.

The simplified system for mounting the printing drum 12 enables the drum itself to be fabricated in a much more simple fashion than known heretofore. Thus, the drum may be fabricated by first forming the ends 22 and 26 with recesses 60 and 62 through the employment of conventional fabricating means such as, for example, dieforming or spinning, and then welding the ends 22 and 26 to the perforated cylindrical portion 75 of the drum to establish an integral, simplified drum configuration. Small variations in the axial length of drum 12 due to manufacturing tolerances are compensated for by spring 90 which will allow some axial movement of support shaft 24 relative to knob 80 without upsetting the seating of the knob against face 94 of the hand wheel or the proper engagement and seating of the arbor members 40 and 42 within recesses 60 and 62.

It is apparent that the printing drum mounting construction enables a simplified construction and operation in a duplicating machine not obtained in the prior art. Changes in registration may be accomplished without requiring direct handling of the drum by the operator, thereby eliminating the annoyance of touching an inkladen surface. Such changes may be made by merely turning the hand wheel after the knob has been employed to disengage the drum from the drive means. Very fine adjustments of registration are possible and the adjustments are infinite rather than being confined to fixed increments.

It is to be understood that the above detailed description of an embodiment of the invention is presented by way of example only. Various details of design and construction may be modified without departing from the true spirit and scope of the invention as set forth in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a duplicating machine having a printing drum including a generally cylindrical body extending axially between opposite ends, a system for mounting and rotating the printing drum within the machine, said system comprising:

support means mounted for rotation within the machine adjacent each end of the printing drum, at

least one of which support means includes a first generally frusto-conical surface coaxial with the axis of rotation of the printing drum; drive means engaged with the support means which includes the first generally frusto-conical surface for rotatably driving the so-engaged support means;

mounting means in each end of the printing drum, each including a configuration complementary to the corresponding configuration of the support means adjacent the corresponding end of the printing drum for mounting the printing drum in the machine between the support means, at least one of which mounting means includes a second generally frustoconical surface coaxial with the axis of rotation f the printing drum and cooperatively engaging the first generally frusto-conical surface with sufiicient gripping force to effect concurrent rotation of the printing drum and the support means which includes the first generally frusto-conical surface; and

means for selectively displacing at least one of the support means axially relative to the other of said support means to accomplish selective disengagement of the driven support means from a corresponding mounting means and permit selective rotation of th printing drum through any desired angular displacement relative to the disengaged driven support means and re-engagement of the driven support means with the corresponding mounting means after such angular displacement of the printing drum.

2. The invention of claim 1 including means for permitting displacement of at least one of said support means axially relative to the other of said support means until the support means are spaced apart axially a sufiicient distance to permit disengagement of all such support means from the corresponding mounting means and allow lateral removal of the printing drum from between the support means.

3. The invention of claim 1 wherein:

each of the support means includes a generally frusto conical surface coaxial with the axis of rotation of the printing drum;

each of the mounting means includes a generally frustoconical surface coaxial with the axis of rotation of the printing drum and cooperatively engaging the corresponding generally frusto-conical surface of each support means; and

a member of elastomeric material is associated with the engaged frusto-conical surfaces of each support means and mounting means such that at least a portion of one of the engaged frusto-conical surfaces of each support means and mounting means is pro vided by said member of elastomeric material to establish a frictional gripping force between corresponding engaged support means and mounting means. i

4. The invention of claim 3 including disengaging means for disengaging the driven support means from the corresponding mounting means in response to the displacement of said one of the support means axially relative to the other of said support means while the remaining support means will remain engaged with its corre* sponding mounting means.

5. The invention of claim 4 wherein said disengaging means includes a pad of elastomeric material normally compressed between the driven support means and the corresponding end of the printing drum when the driven support means and the corresponding mounting means are engaged.

6. The invention of claim 4 wherein said disengaging means includes a difference in the hardness of the clastomeric materials associated with the engaged frusto-conical surfaces, the hardness of the elastomeric material associated with the frusto-conical surface of the driven support means being less than the hardness of the elastomeric 7 material associated with the frusto-conical surface of the remaining support means.

7. The invention of claim 4 including:

means for manually rotating said remaining support means relative to the driven support means when the driven support means is disengaged from the printing drum to rotate the printing drum relative to the driven support means; and

indicator means in fixed relationship with the driven support means for indicating the amount of such relative rotation.

8. The invention of claim 1 wherein:

the mounting means include a recess in each end of the printing drum, each recess extending axially into the body of the printing drum and having a frustoconical surface around the perimeter of the recess; and

the support means include first and second arbor members, one adjacent each end of the printing drum, each having a frusto-conical surface received within a recess and engaging the perimeter of the recess with sufiicient frictional gripping force to effect concur rent rotation of the printing drum and the arbor members.

9. The invention of claim 8 wherein:

the drive means is engaged with the first arbor member; and

the means for displacing at least one of the support means axially relative to the other include a shaft fixed to the second arbor member and mounted in the machine for axial movement relative to the first arbor member for displacing the second arbor member axially relative to the first arbor member.

10. The invention of claim 9 wherein said shaft is mounted for selective axial movement to a position where the second arbor member is spaced axially from the first arbor member a sufficient distance to permit disengage ment of both the first and second arbor members from the corresponding recesses and allow lateral removal of the printing drum from between the arbor members.

11. The invention of claim 8 wherein the apical angle of the engaged frusto-conical surfaces is small enough to effect frictional locking engagement between the engaged surfaces for concurrent rotation of the printing drum and the arbor members and great enough to per mit selective ready disengagement of the arbor members from their corresponding recesses by axial displacement of one surface relative to the other.

12. The invention of claim 11 wherein said apical angle is in the order of magnitude of 15 13. The invention of claim 11 including a member of elastomeric material associated with the engaged frustoconical surfaces of each arbor member and corresponding recess such that at least a portion of one of the engaged frusto-conical surfaces of each arbor member and corresponding recess is provided by said member of elastomeric material to establish the necessary frictional gripping force between the engaged frusto-conical surfaces.

14. The invention of claim 13 including disengaging means for disengaging the first arbor member from the corresponding recess when one of said arbor members is displaced axially relative to the other of said arbor members While the second arbor member will remain engaged with its corresponding recess.

15. The invention of claim 14 wherein said disengaging means includes a pad of elastomeric material normally compressed between the first arbor member and the cor- 3 responding end of the printing drum when the first arbor member and the corresponding recess are engaged.

16. The invention of claim 14 wherein said disengaging means includes a difference in the hardness of the elastomeric materials associated with the engaged frustoconical surfaces, the hardness of the elastomeric material associated with the frusto-conical surface of the first arbor member being less than the hardness of the elastomeric material associated with the frusto-conical surface of the second arbor member.

17. The invention of claim 8 wherein the first and second arbor members each include a generally annular member of elastomer material providing the frusto-conical surface of each said arbor member.

18. The invention of claim 17 wherein: the drive means is engaged with the first arbor member; the means for displacing at least one of the support means axially relative to the other include a shaft fixed to the second arbor member and mounted in the machine for axial movement relative to the first arbor member for displacing the second arbor member axially relative to the first arbor member; and

the invention includes disengaging means for disengaging the first arbor member from its corresponding recess in response to displacement of the second arbor member axially relative to the first arbor memher while the second arbor member will remain engaged with its corresponding recess.

19. The invention of claim 18 wherein said disengaging means includes a pad of elastomeric material normally compressed between the first arbor member and the corresponding end of the printing drum when the first arbor member and the corresponding recess are engaged.

20. The invention of claim 13 wherein said disengaging means includes a difference in the hardness of the elastomeric materials of the annular members, the hardness of the elastomeric material of the annular member of the first arbor member being less than the hardness of the elastomeric material of the annular member of the second arbor member.

21. The invention of claim 8 wherein the nominal diameter of the frusto-conical surface of each recess and the nominal diameter of the corresponding frustoconical surface of each arbor member is great enough in proportion to the diameter of the printing drum to maintain axial alignment of the printing drum within the machine during rotation of the printing drum and to provide sufficient engaged surface area at the engaged frusto-conical surfaces of the corresponding arbor members and recesses to effect concurrent rotation of the printing drum and the arbor members.

22. The invention of claim 21 wherein the nominal diameter of the frusto-conical surface of each recess and the nominal diameter of the corresponding frusto-conical surface of each arbor member is in the order of magnitude of one-half the diameter of the printing drum.

References Cited UNITED STATES PATENTS 2,425,928 8/ 1947 Emerson. 2,677,971 5/1954 Greenwood l0l248 XR 2,819,670 1/1958 Newcomb et al 101-38 ROBERT E. PULFREY, Primary Examiner.

C. D. CROVVDER, Assistant Examiner. 

